The Value of a Computer over its Lifetime

April 13, 2020

I’m currently in the process of compiling a presentation on “Collecting Old Computers as a Hobby” for the upcoming VCFB 2020 event. I’m not sure whether it really fits in that presentation, but I made a highly speculative, subjective chart on, what I think, the value of a computer over its lifetime looks like. Here it is:


Let me explain. First, I differentiate the lifetime of a computer into 4 phases.

The “phase of usefulness” starts when the model comes onto the primary market, i.e. when it’s new. Obviously, the manufacturer thinks that it will be bought because it offers some benefit to the buyer. It is sold at the initial price (which typically will decrease over the time the model is offered by the manufacturer). I think it is not unreasonable to assume that the value of the computer, once bought, drops exponentially in this phase, especially when it it a state-of-the-art model. As it approaches the end of the usefulness phase, it typically drops to a more symbolic value that is basically determined by the minimum amount a seller is willing to accept in order for the entire transaction to make sense at all (i.e. compensating for the effort of the seller to offer, handle, and sell the thing. If the offered price would be any lower, it would not be worth the effort of the seller to do anything. If this computer model was bought originally by a company, it is most probably written off since some time anyway, to the company cannot put any value on it. The length of this phase depends probably on different factors, but maybe something like 10 years is not completely wrong for a computer. This phase transitions into

The “garbage phase“. The computer has no usefulness anymore, but it is not so old already that there are sentimental feelings connected to it. In this phase, the value is minimal and probably quite stable around the symbolic value I tried to establish in the last paragraph. Maybe in this phase it is not handled by the original owner, but by traders who specialize in surplus goods, making the price of the computer maybe even a tad lower because such traders are more efficient at low prices. I put a length of this phase also at around 10 years and try to substantiate that in the next paragraph, because the next phase is

The “sentimental phase“. This phase has a lot to do with the average age of a typical collector of a computer. Typically, they either had this computer model when they where young, or they were around when this model was fresh on the market. Since this phase probably 20 years or more has passed and they remember this time in retrospect with positive feelings (who does not remember his/her youth with joy? The music was much better than nowadays, the world was not that complicated and there was much less hatred and selfishness in the world). Also, being his his/her late 30s, 40s, and early 50s, things start to settle down for yourself. Often, there is less shortage of money, and less time needed to find a partner. For sure you don’t have a midlife crisis, but all this urge to buy a motorcyle… 🙂 Now, this is the time to feel young again with the dream machines of your youth, to fulfill unfilled dreams of owning cool stuff for a bargain. As a result, people start collecting computers. This process starts slowly, only a few people start collecting, but now the prices raise again. More and more people collect computers, maybe collecting becomes cool, and , with the raising prices, maybe even a good opportunity to invest money.

My theory is that the prices of a computer a collector wants to buy are:

  • not dependent on the initial price
  • dependent on a bunch of other factors, e.g.
    • how rare the model is
    • how many other collectors the model want
    • and, almost more importantly, what the buyer is willing to pay for a sentimental, or decorative, or conversation piece

I have also the impression (although I did not invest time into this to prove it) that these new values are clustered (and I put some estimation of how large these clusters are in the figure). Also, these price clusters increase over time as inflation and salaries increase over time. Finally, people think that the prices will go up forever and start thinking of them as investments (which will draw in also non-collectors that will act as investors).

This phase ends when the majority of the collectors starts getting so old, cool stuff from one’s youth is getting less important. This happens when no younger collectors replace the old ones, e.g. because the age of computers being cool stopped at some point. There are some areas where new collectors seem to continously “re-grow”, e.g. art and antiquities. There are other areas that flourished over many years, but suddenly came to a lack of collectors, e.g. stamps. My assumption is that, as computers became utilitarian in the 2000s instead of being fresh and not understood by parents, they aren’t as magical to millenials as they are to earlier generations (this is probably different to consoles and game-related computing, these will probably thrive much longer). If my prediction is correct, then prices at the end of this phase will drop dramatically as the market vanishes and the budget per collector gets much smaller.

It is also no clear to me what the next phase after the sentimental one is, and how this changes the prices for old computers.

In summary, here some conclusions:

  • most computers have their highest value when they are sold initially
  • the best phase to buy an old computer is the garbage phase (which is long gone for computers up to the year 2000)
  • do not buy old computers as a long-term investment

So, here you have it, my wild, highly speculative look into a crystal ball. What do you think?

BURP – Basic Using Reverse Polish

March 21, 2020

Recently, I did not buy a new old computer. I did not buy it because I was outbid in a real auction in the UK (by twice the amount I was ready to pay, not to mention the 33% fee on that price for the auction house and the VAT, nor the additional cost to package and ship the whole thing). However, I am very ok with not having bought it, because it would have been a kit computer of unknown state, there wasn’t any documentation with it, and it featured only a Z80 CPU. The only three redeeming qualities of this model are its rarity, its use of a mathematical co-processor, and its unusual programming language. So, I decided to proceed as if I had bought the computer, and write about the programming language.


The computer was a Powertran PSI COMP 80 computer (sold for 420 GBP + commission). It is a relatively early (1979) design published by the British magazine Wireless World and used as a basis for a singleboard computer sold as a kit by a British company called Powertran. Z80 CPU, 8 kB of RAM and EPROM, 2 kB of video RAM, monochrome graphics of 128×64 pixels or 64×32 characters: not an usual design for that time. What made this model a little bit special was the use of a mathematical co-processor, a National Semiconductor MM57109N.

But let’s start at the programming language of this computer. It is called BURP, “BASIC Using Reverse Polish”. The reverse polish notation is the thing where you first specify the parameters of a function (which are pushed on a stack), and then you specify the function name. When the function is called, it takes its parameter from the stack, calculates the result, and pushes it back on the stack. This is the (still quite exotic) basic principle in Forth, some early HP pocket calculators, and Postscript. So, if you would write something like add(10,33) in any conventional programming language (requiring a parser to translate this code into something a computer understand), in reverse polish notation that would become “10 33 add” with the semantics “put a 10 on the stack, then a 33, then call the add function, who will take the two parameters from the stack and put the result (43) back on the stack for the next function to use”. This notation allows for quite compact interpreters, but the programmer has to manage the stack herself.

I like Forth a lot so I thought, ok, this is funny, a BASIC with a reverse polish notation should be quite quirky, ending up in programs like ’10 “Hello, World” print 20 10 goto’ if this type of basic also supports line numbers. However, BURP is even more strange than that because not all commands use the reverse polish notation, but only expressions. The rest of the syntax is still conventional infix notation.

All this strangeness has a reason: the mathematical co-processor. As [Carver] puts it, “The constraints of the MM57109, which was essentially a dedicated calculator chip with a 4-bit microcontroller interface bus, strongly affected the design of the language. Significant features of the language include a fixed set of 26 numeric variables (A-Z), a maximum of 256 lines of code, a three-deep hardware stack for expressions, a limit of one for-loop at a time (so no nesting, not even in GOSUBs) and no string processing (except implicit concatenation of static text and numbers during output.)” Oh yes, plus the MM57109 talks to the world in reverse polish notation.

Ok, so the number calculating part of this BASIC by and large represents the format which the math processor needs. So, how does a BURP program looks like?

Example: LET C = 3 SQ 4 SQ + ROOT

Here, we assign a value to a variable C. This value is SQRT(3^2 + 4^2). First, the 3 is put on the stack. Then, a “squared” operation is called on the 3, replacing it by 9. Then, the 4 is put on the stack, and then replaced by 16. Now, and add function adds the 16 and the 9, replacing it by 25. Finally, the square root is taken, so in the end, the only number of the stack is 5, which is assigned then to the variable C (actually put in register C of the math chip).

The National Semiconductor MM57109 (the original data sheet titles it as a “Number Cruncher Unit”) is from 1977. It is the mask-programmed derivate of the MM5799 chip, which is the 2-chips-in-1-version of the 5781/2 chip set, the calculator chip family of National Semiconductor. It added 70 mathematical functions to the MM5799 design. From the viewpoint of a computer manufacturer, this is very attractive, because a) you don’t have to write all this math code yourself, b) it is efficiently executed. However, the MM57109 was not really an FPU (floating point unit) like modern math co-processors (which are nowadays integrated into the CPUs). First, the unit processed numbers that came in up-to-8 decimal digit packets (coded as 4-bit BCDs). Second, “Instruction execution times range from 1 ms to 1 second” (according to the data sheet). ONE second. That makes total sense for a calculator, but not too much sense for a computer. However, “real” FPUs did not exist much before 1977, with AMD’s AM9511 being one of the first.

So, here you have it. An early kit computer with a calculator chip as a mathematical co-processor and a crazy BASIC that makes complete sense in this design. Burp. Happy digesting.


Canon object.station 41

March 8, 2020

1989 Canon bought 16.6% of NeXT, Inc. for $100 million. Canon also produced the MO drives that the early NeXT models were based on and also served as NeXT’s distributor in Japan. 1992 Canon added another $30 million (other sources say $55 million) to this sum in order to keep NeXT afloat. In 1993, NeXT decided to exit the hardware market and to become a software-only company.

It is not clear why Canon did the next step, but probably Canon thought that their investment in NeXT might be in danger. NeXT might not feel being a hardware company any longer, but certainly Canon was (and still is). NeXT would take care of the OS side, so why not produce hardware especially suited to the NeXTStep OS, but at the same time chosing a less exotic architecture, thus saving development cost? This might have been the thoughts of Canon when they bought a license from NeXT to use NeXTStep on their hardware (they seemed to try to get even the NeXTStation brand to use for their models, but failed).

Canon and NeXT were even in negotations about both buying NeXT’s Fremont factory as well as some hardware development department, which at the time, was developing an 88000-based NeXTStation. However, we know that the factory was not sold in the end, and so was probably also the development department (because else we might have seen a different machine).

What Canon ultimatively came up with was a PC architecture. It was certainly high-end, with SCSI-2 and a quite full set of features, but it was also a machine you could install Windows NT on (and I mean the Intel version). This is not to say it was a completely ordinary, unmodified PC, because there are some peculiarities.

But, sorry, I completely forgot to introduce to you the topic of this post: Meet the Canon object.station 41.


As mentioned before, this computer has a conventional PC architecture, albeit with a more high-end set of components. It uses an Intel 486DX mit 100 MHz, has 16 MB of RAM (up to 96 MB), an integrated 500 MB SCSI harddisk, a CD-ROM drive and a 3.5″ floppy disk drive. It came pre-installed with NEXTStep 3.3. It had also Insignia’s SoftPC pre-installed, so you could use PC programs from NEXTStep. I think this is very funny, with the machine being a PC… It came with a Logitech PS/2 mouse and a PS/2 keyboard that included NeXT-specific keycaps, controls for audiovolume and monitor brightness.

The only special thing the computer has is the graphics system. It is not a mere graphics card, but a proprietary Canon architecture based on Chips & Technologies Wingine technology. It is a 64200 Wingine together with a modified Brooktree Bt485 RAMDAC to support the internal 4-4-4 color representation of NEXTStep and had 2 MB of VRAM and up to 1280 x 1024 16-bit color resolution. The hardware had been optimized to be between 15% and 30% faster than a standard Intel Pentium PC running NEXTStep. The CD-ROM delivered with the system therefore did not only had the NextStep on board, but also drivers for Windows NT.

Blake Patterson wrote in a 2007 BYTECellar blog post about the Wingine: “WINGINE was designed by Chips & Technologies to be an extremely high speed framebuffer requiring motherboard support in the form of a C&T chipset and a proprietary local bus WINGINE slot into which the WINGINE graphics board was inserted. This made the system one of the preferred graphics configurations for NEXTSTEP, as the operating system did not employ any 2D graphics acceleration – all it wanted was an extremely high bandwidth video subsystem. (Graphically intensive NEXTSTEP was the first OS to feature “solid drags” of windows which, at the time, was a rather heavy lift.) […] The WINGINE also utilized expensive, dual-ported VRAM as opposed to cheaper DRAM for optimal speed.” Epson and JCIS were two manufacturers who offered motherboards featuring the Wingine local bus slot.

In the object.station 41 however, the graphics is directly contained on the proprietary Canon motherboard. In the local bus slot there is a riser board, and in the VL bus slot of the riser card the SCSI-2 card (a Buslogic BT-445C VL-Bus controller) is contained (parallel to the motherboard. The riser card allows for the small height of the pizza box case, and contains 3 ISA slots.

The object.station 41 was not the only member of the family. Allegedly, there was also an object.station 31, and a 50 and 52. The 31 from 1995 had the same case, but was missing the SCSI-2 card. The 50 and 52 introduced in 1995 had Pentium processors and seem to come in black mini tower cases that do not look different from any other case. The 50 seems to have a 100 MHz Pentium and the 52 a 120 MHz Pentium. I’m not sure whether the 31, 50, and 52 models were sold at all or in numbers. There is one photo of probably a 50 out there, but that’s basically it. The least rare model is the 41.

The model I have unfortunately misses the harddisk and the CD-ROM drive, but I think this might be less of a problem.

The Canon object.station series seems to be very unsuccessful. I’m not sure whether there is a point in asking why because the better question should be: Why should it have been successful in the first place? NeXT did not develop hardware anymore because it sold badly, NeXTStep 3.1 was available for HP’s PA-RISC CPUs, Sun’s SPARC, and for PCs, and the modifications Canon added to a standard PC architecture weren’t exactly killer features. There was simply no reason to buy an object.station. And so an object.station is a very rare find, much rarer than any original NeXT hardware.

Technical Data

Manufacturer: Canon
Model: Object.Station 41
CPU: Intel 486DX4@100MHz
RAM: 16 MB (up to 96 MB)
Resolution: max. 1280×1024
Color: 16 bit
Interface: Fast-SCSI-2, Ethernet, parallel, 2 * serial, keyboard, mouse, video, microphone, headphone, stereo out
Drives: 500 MB HDD, CD-ROM, 3.5″ floppy disk drive
OS: NEXSTEP, Openstep, Windows NT
Released in: 1994
Initial price: $5000



Unusual Sony Notebook Drive Bay Modules

February 29, 2020

It is not completely unheard of to have a modular bay system for notebook computers, having the possibility for the user to chose whether to have an optical drive there, or maybe an additional battery, or the like.

But I think that there was a decision meeting missing after a brainstorming session at a Sony computer department when they came up with these additional bay modules:

PCGA-CWN1 Compact Woofer

Yes, this is a woofer. It works because it seems that the bays were open at the bottom:


PCGA-TKN1 Number Pad

Yes, it is exactly what you think it is – an additional number pad you can flip out of the bay:


And, no, these were actual products, no photoshopped fakes.

Not crazy, but also quite unusual is this bay module:

PCGA-MDN1 Net MD drive

Yes, that’s a MiniDisc drive for a notebook.


NCR Safari 3115

February 27, 2020


Recently, on ebay, I stumbled upon another NCR mobile, pen-based computer. In contrast to my beloved 3125s, I have never heard of it.

It looks like the older, smaller, much uglier brother to the 3125, but it is not. It is the much rarer, smaller, much uglier, younger brother of the 3125: the Safari 3115.

“Safari” already hints to the time it was released, because Safari is the family name of the AT&T mobile computers. NCR was taken over by AT&T in 1991/92, so this release must be later than that.

Now, the model designation 3115 puts it in the NCR 3000 family, below the 3125, but the “3000 family” was always a marketing lie as the computers in it differ a lot architecture-wise and OS-wise.

The operating system of the 3115 was Windows 3.1 with pen support. The RAM seems to consist of a DRAM card that is accessible via the interface bay. Mine is a Samsung 4 MB model. It is labelled “ICMC V4.1” which is the same as PCMCIA 2.0.

There is an “unofficial NCR (Safari) 3115 support page” which holds most of the information on this machine, but it seems to updated last in 2000…

It weighs 1700g, so it is even 200g heavier than the A4-sized 3125… And although the outer area of the 3115 is smaller than the one of the 3125, the outline volume is probably about the same or even larger!

The Computer History Museum even has a docking station called “CommStation” for the 3115.

I did not think that this machine even deserves more research, because, boy, it is ugly, and because there were a lot of Windows-based pen tablets out there after 1991.

However, I opened the case to see what’s inside because some things (like the concrete CPU model) are not even known. And I have to say, the inside is more advanced than what I thought it it would be.


What I was surprised first was the fact that the computer seems to be at least splash-proof. There is a thick seal in between the case halves, and most of the interfaces are put behind rubber plugs. There is not even an electric interface connecting the machine to the docking station, but an array of infrared LEDs.

The second suprise was that most of the weight seems to be contained in the display which is secured in a metal case. The PCB is not very large, the case not that heavy.

The final suprise was the “harddisk”. It is not a harddisk, it is basically the second generation prosumer-grade SSD in form of a SunDisk(sic!) SDI-20 20 MB SSD with a date of 1992-1993. The first generation was developed by SunDisk (now SanDisk) for the original IBM ThinkPad in 1991. It had a capacity of 20 MB and costed $1000. Obviously, an SSD is much more suited for a rugged pen-based computer than a rotating harddisk.

Other things I found inside were: an Intel 80486SX CPU and 4 MB of soldered RAM.

So, here is my final verdict: This was an attempt to created a rugged, small, pen-based Windows tablet. Unfortunately, it is way too heavy and ugly. Although I don’t know the original price, it probably have not been cheap. It is more interesting that what meets the eye and it is a very, very rare thing.

Technical Data

Manufacturer: NCR
Model: Safari 3115
CPU: Intel 80486SX@25 MHz
RAM: 4MB (8 MB max)
HDD: 20-40MB
Weight: 1700 grams
External dimensions: 23cm*23cm*7cm
Pen: Cordless 1 button digitizer pen made by CalComp Inc, transmits on R/F ranges 0.0576Mhz and 0.0614Mhz, runs on 4(E 393 buttoncell batteries)
Display: 6.25″ Backlit Monochrome VGA
OS: MS-DOS 5.0/Windows 3.1 with pen support
Interfaces: 1 RS232C DB9 serial port, 1 Centronics 25-pin Parallel port, 1 PS/2 Keyboard port, 2 PCMCIA-II expansion slots, 1 PCMCIA-1 memory card slot, 1 Infrared communications/docking port, 1 external power/charging connector
Battery: 9.6V (NIMH) 1200mAh, 1.2A, good for 4hrs per charge?
Released: 1993
Initial price: ???


Sony NEWS Portable Workstation NWS-1250

February 27, 2020


We do not see many vintage Japanese workstations in the West. We also do not see many portable workstations (of any make). So, what we really rarely see, are Japanese portable workstations. I feel quite fortunate to have recently acquired one, even if it is not working as of right now. But, once more, let’s start at the beginning.

Sony is, by-and-large, a consumer electronics company and is well-known for their MSX offerings back in the day and their VAIO line of PCs until quite recently. Not so well known is the fact that Sony produced classic workstations from 1987 to 1995. By “classic” I mean they started off by Motorola 68k-family CPUs and ending in RISC CPUs, and they used Unix as their operating system.

The story of why Sony was producing a class of computers that did not really fit their usual lineup goes like this: The manager of a newly established computer project wanted to create a new, cheap office computer, but his engineers wanted instead to do a computer that would replace the VAX 11/780 that was hard to get computer time on, but which they used in earlier projects. The manager settled with the wishes of his engineers and out came a machine that gave each engineer his own substantial, graphical compute power. Now, the concept of workstations is well known in 1986, but Sony competes in the market via the cheaper price and the better price/performance ratio.

The first generation of Sony workstations (1987-88) had mainly dual 68020 CPUs in them and often a Motorola 68881. The second generation (1988-90) used a single or dual 68030 CPUs and a 68882 mathematical co-processor. The third generation (1989-95) used MIPS CPUs, first a R3000, then an R4000, R4400, R4600, R4700, and the final model in 1995 used a R10000.

The operating system, NEWS-OS, was first a BSD variant, in later iterations an System V derivate.

In the long list of 60 models Sony produces, there are also two models (with two variants each) of portable workstations. Both models use the same case and look the same.

The earlier models, the NWS-1230 and NWS-1250, are second generation and have a single 68030 CPU and a 68882 co-processor. They are released in 1990 at a price of 1,250,00 and 1,550,000 Yen, respectively. The slightly larger model, NWS-1250 is the one I got.

“Portable workstation” here does not mean laptop computer, although it is certainly possible to place it on the lap. But without a battery, a weight of about 8 Kg, and measuring 35x42x10cm this is not exactly something you pack in your bag. The machine contains a black-and-white LCD, a keyboard, a 3.5″ floppy disk drive, and a (SCSI) harddisk.

How rare were portable Unix workstations at that time? Let’s have a look at the competition in 1990. There are, of course, many portable PCs available, although typically not of a workstation class. The only other portable Unix workstation that I found before 1990 are the 1985 HP IntegralPC (with a 68000 CPU and Unix in ROM) and the 1989 Opus Portable Workstation (with a 88000 CPU) for $14,000. The next models that I found are the 1992 Tadpole SparcBook 1 and the 1994 Sun SparcStation Voyager. All in all, it seems to me that in 1990 there weren’t many portable Unix workstations around (if you do not count PCs with Unix). And also: why should there be battery-less portable Workstations? The main use is probably showing potential customers your Unix programs, and that is a real niche market.

However, the design of these portables is still quite beautiful and thought-through. When you close the lid with the LCD, it brings your keyboard in a horizontal direction and basically seals it off so no dust can enter in transport. When you open the lid, the keyboard swings down a few degrees, giving you a nice typing angle.

Apart from the design, there is nothing too special about the hardware except the audio capabilities. This machine has dedicated headphone and line in, and mic sockets right at the side of the keyboard. There is also an “MIC ATT” switch (0 db and -20db) and one that switches between mono and stereo. There is dedicated audio hardware onboard, but I do not know the concrete characteristics of that.

Now, my machine is not functional because it lacks a harddrive. These things used SCSI drives and were purportedly picky with which model they chosed to collaborate (there is one guy who says that the kernel has a list of allowed harddisk models). My model had a 240 MB harddisk, probably a Hitachi DK312C-25. Let’s see whether I bring it to life, one day.

Technical data

Manufacturer: Sony
Model: NWS-1250
CPU: Motorola 68030@25 MHz
FPU: Motorola 68882
RAM: 8 MB, extendable to 12 MB
Harddisk: 240 MB
Floppy Disk Drive: 3.5″, 1.44 MB
Display: 11″ b&w LCD, backlit
Graphics: 1120×780
Interfaces: mouse, audio (phones, line in, mic in), SCSI, Ethernet (AUI), serial (DB9), parallel (proprietary), SCSI (SCA?)
Released: 21.07.1990
Initial price: 1,550,00 Yen (or 25,000 DM)


A few remarks on the Canon Cat

February 23, 2020

I’m currently writing a German article for the club journal (“LOAD“) of the VzEkC (basically the national German vintage computer club).

Here are some remarks that did not fit into my article.

Cat Manuals

There is a whole load of manuals for the Cat available electronically. Simply visit for the

  • How-to Guide
  • Reference Guide
  • Online Help (the files from the Cat ROM)
  • Tutorial (the file from the Cat ROM)
  • Quick Reference Card
  • Hardware Schematics
  • Workshop Manual
  • Technical Documentation for the Canon Cat Editor
  • tForth Manual

LEAP in the 21st century

One of the main features of the Cat was Jef Raskin’s LEAP technology. It is basically a fast search-in-the-entire-document-space (in the memory of the Cat) plus moving the cursor to the found location. If you can remember a name, a location, or a phrase, you can find the corresponding location across all documents on the Cat.

This would be a useful function even (or especially) today if you could do it over all things you have ever typed in on all machines that you have ever used. It would require some technology to track all things typed in by a user, but nowadays we have enough compute power to search in that type of data amount quickly.

Finally, although there is a lot of things you can find about the Cat electronically, I received with my machine some things that I did not find in the Internet.

Canon Cat prospectus

It seems to me that this must be the standard marketing material.








Obviously, there was also a little bit oft software for the Cat. I do not know whether these would be sold separately, whether the shop simply copied them to customers, or what their status was. For the CATFILE program a “Note to dealers” basically says that this should be given out to customers so they “will appreciate this usefull addition to their Cats, and we hope they will be encouraged to tell their friends and business associates about this recent upgrade to their Cat systems”. Does not sound as if the Cat sells itself easily, does it?

CATFORM is a Cat program that allows to manage forms on a Cat and to print them out. You can create, store, and fill out forms with this program. I have a printed manual for that. This manual is also available electronically under:

CATFILE allows yout to manage name and address lists on the cat and to use them for mail merge. I have a printed manual for that.

CATFILE Utility Disk
Now this program is not directed towards the users, but towards the dealers. It “is used to create and customize the Catfile Application Software disks for your customers use. I have a photocopied manual for that.

“Secretarial Workstation” demo disk and marketing material
This package was meant for dealers to demonstrate the “secretarial workstation” potential to potential customers. To that end there was a demonstration disk and a short printed manual that explained how to use the disk.

Family Tree v2.1
I do not know what this app really is. Obviously, it is some form of tool to record data for a Family Tree, but I do not know whether this was a commercial program or whether the last owner did program this himself.

BTW, if everythings works out, I will show off my Canon Cat (and the software) at the Classic Computing 2020 exhibition in Thionville, France on the 26th and 27th of September 2020.

Western Digital Pascal MicroEngine, an Update

February 16, 2020

Yesterday, I received a 2nd MicroEngine board, unfortunately in a worse state than my first one. Also, probably an earlier patch level as there is less patch cableing on the board. Nevertheless, nice to have.

Also, if you look for images for boot floppy disks, you can find them under

Umtech VideoBrain Family Computer

January 10, 2020

Recently, while searching for another computer, I found a computer in a box in another box that I obviously bought some years ago, but then completely forgot about it. What was even funnier is that I saw this exact model on ebay some days ago and actually thought about bidding for it (which I didn’t). This computer finally sold on ebay for over €850 or $960 even without power supply or joysticks. I do not remember, but I am pretty sure I did not pay that type of money whenever it was that I purchased it.

Okok, to the point: Let me introduce you to the VideoBrain, sometimes also called the VideoBrain Family Computer, the sole model produced by a company called Umtech from 1977 on.

Very unusual for a home computer was the full travel, 36-key keyboard it featured. However, it is said to be poorly designed and difficult to use. Certainly, the choice of functions on it looks very weird.

The VideoBrain had no built-in computer language. However, there was one language available as a cartridge from December 1978. If you would had to guess which language one should offer to home consumers, only a few people would come up with the choice of VideoBrain: APL/S. APL is a programming language which (according to its Wikipedia page) is influenced by “mathematical notation” and influenced itself such crowd pleasers as “MATLAB” and the “Wolfram Language” :-).

Regarding the VideoBrain and APL/S there is a magnificient audio recording from the Third West Coast Computer Faire conference in 1978. This recording was made during the presentations of the Conference. Thir first and second presentation are:

  • Ted Haynes: Videobrain and the APL/S Language
  • Robert G. Brown: An Introduction to APL/S: A Modern Computation Language for Personal Computing

and you can listen to them in very good quality using the last link in the references.

And, you heard it here first, the $150 APL/S cartridge actually had not only ROM, but also more RAM (if you listen to the presentations from the last paragraph). This is also hardly surprising as 1 kB of RAM is hardly enough for a (later) Sinclair ZX81 with its efficient, token-based program representation, let alone APL, a language that can handle entire number arrays with a single operator. <update>[Brown78] states that the cartridge had 13 kB of ROM and 1(!) more kB of RAM.</update>

When you listen to the presentation of Robert G. Brown, you can also hear his rationale of offering APL as opposed to Basic, namely the higher productivity and better degree of programming structures. These are, of course, honorable reasons for a computer scientist, but seem a little bit odd for an entry-level computer with hardly enough memory to actually have program readability problems :-).

The above presentations are also contained as text articles in the Proceedings of the Third West Coast Computer Faire conference. But if you are interested in the APL dialect, also Byte had an article by Robert G. Brown, the author of APL/S in the December of 1979 issue, and this issue is online (see references below).

The main differences of APL/S to APL are:

  • APL/S is a subset of APL
  • all these pesky special characters the original APL needs as operators (like the arrow and the star-im-a-circle) are replaced by ASCII strings
  • arrays in APL/S are restricted to one dimension and subscript expressions must evaluate to scalars
  • APL/S adds control structures like IF and WHILE

APL/S uses a two-part user interface. In the lower half the user can enter and execute code. The upper half is reserved for bar charts. For variable names, only the first four characters are used.

The VideoBrain was the first home computer system where the software was available as cartridges. These could contain of up to 12 kB of ROM. Fewer than 25 software titles were ever markteted for the VideoBrain.

The used CPU is quite old and exotic. It is a Fairchild F8, which consists of two chips (the CPU and the “Program Storage Unit”. This sounds awkward, but was actually a technical achievement in 1975, at a time when earlier CPU designs distributed the needed functionality over a larger number of chips (sometimes 7 or more chips). Later on, CPUs assembled all functions in one chip. As a result, the F8 was quite economic, which, according to [CPU Museum], made it in 1977 to “the world´s leading microprocessor in terms of CPU sales”. However, as we know, the number of computers exploded only after 1977, and these computers used other CPUs. Therefore, it is not surprising, that there aren’t that many F8-based computers. There is the VideoBrain, and there is Fairchild’s own console, the Channel F Video Entertainment System from 1976.

Due to the high cost of RAM at that time, the machine came only with 1 kB. However, it had 4 kB of ROM, providing four built-in programs: a simple text editor, a clock, a count down timer, and a color bar generator.

The basic computer itself does ntot have any possibility to save data, you had to buy the “Expander 1” if you wanted to have cassette tape recorder interfaces (and two RS232 interfaces). The “Expander 2” was a 300 baud modem.

Graphics on this machine seems to be complicated. [SeanRiddle] says “This document describes the VideoBrain grapics hardware. It is a sprite engine, capable of displaying 16 sprites simultaneously. The control registers are documented pretty thoroughly. The sprites are monochromatic, but each can be a different color. There is one bit each for RGB, and 2 bits of intensity info (but maybe only 2 intensity levels are usable). The registers allow for a sprite up to 248×256 pixels, positioned on a grid 256×512 pixels in size. Sprites can be displayed at twice their horizontal or vertical size. There are 2 “display lists” for setting the y position and drawing priority of the sprites. There is also a mode called “xcopy” that replicates the first byte of a sprite horizontally.”

The computer was not widely available, but was sold for a short time by Macy’s department store. As you can imagine, the VideoBrain was not a large success, and it vanished from the market after 3 years.

The Wikipedia article on the VideoBrain talks about the fact that the VideoBrain had no real defined target audience and therefore could not satisfy anyones needs (in contrast to the Apple II), and that’s certainly true. From my point of view, the VideoBrain tried to be both a games console (small memory, cartridge slot, 4 joystick interfaces, no cassette interface) and a computer (full keyboard, programming language available from 1978, computer interfaces available in expansion module), but did both things badly.

Technical Data

  • Manufacturer: Umtech
  • Model: VideoBrain Family Computer
  • CPU: Fairchild Semiconductor F8 @ 1.79 MHz
  • RAM: 1 kB
  • ROM: 4 kB
  • Graphics: 16 colors, sprite engine (see above)
  • Interfaces: 4(!) joystick ports, TV RF connector, cartridge, expansion port
  • Released: 1977
  • Initial price: $500 (basic device)


Gepard – Part Seven: The Gepard Company

January 6, 2020

As with many startup companies, the history of the Gepard company is very intense, but unlike many unsuccessful startups, it is both rather short *and* produced tangible results in time.

So, let’s start at the beginning.

It is the year 1983. The computers in the consumer market are mainly 8-bit computers. It is already clear at this point that the Next Big Thing will be 16-bit computers, but in Germany you can buy 16-bit computers only as expensive, professional computers. Examples for these models are:

  • the HP 9816 (starting at $3895 or about DM 14,000)
  • the Tandy TRS 80 Model 16 (admittedly more a semi-professional machine) at about DM 17,500
  • the Fortune 32:16 at DM 25,000

In the US, there is the “Dtack Grounded” single board computer sporting a Motorola 68000 CPU at the maximally possible 12 MHz. It uses SRAM in order to use this speed, but the board does not offer too much more. The people behind this computer also publish a newsletter of the same name which is informing its potential customership about the current developments regarding this board and the industry.

Having this in mind, a group of friends aims at founding a computer company that targets a computer these group would like to buy themselves. The assumption behind this strategy is that such a computer should meet the needs of a market of similar minded people. The requirements of this computers would be:

  • a Motorola 68000 CPU
  • modular design for maximal flexibility
  • initially designed as an add-on for an Apple II computer because:
    • the friends are Apple fans
    • this approach has the advantage of not needing to develop own UI and storage hardware from the start
    • this allows for a cheaper price for the first product

This company, the “Gepard Computer GmbH & Co. KG” is founded in Oldenburg, Germany in August 1984. The initial founders are:

  • Thomas Schumann
  • Herman Spille
  • Klaus Onnen

Later on, two more founders join:

  • Meinolf Schneider (nowadays: Amekudzi)
  • Bernd Heyer

In order to finance the company, each founder has to contribute DM 40,000. More money is contributed by an investor. The inital round of financing sums up to DM 410,000. A second round adds additional DM 180,000.

In the spirit of Dtack Grounded, also Gepard published a periodical newsletter on paper even before the actual company was started. It informed potential customers and interested parties about the current and upcoming state of Gepard developments, it provided information in different, related topics, and it dissed the competion. The newsletter was completely free. It was published from October 1983 to March 1986 in 12 issues of typically 12 A5 pages in an edition of 500 copies each. The newsletter lead to several contacts, not least it was read by a contact of the later investor of Gepard.

Development of the hardware starts already in 1983. The founders and some first employees design three cards (CPU, RAM, Apple II Interface) for the Gepard, a backplane, an Apple II card (which connects to the Interface card), the Modula-2 compiler, the operating system (GDOS), and the software that runs on the Apple II. They have the PCBs then produced locally (in Oldenburg), buy components, and populate and solder the PCBs themselves. A first run of 30 sets is produced and in 1984 the first sets can be sold to the people who had registered via the newsletter.


Marketing-wise, Gepard was not very active, but tried to get the most out of its limited effort. The main marketing channel was the Apple User Group Europe (AUGE). So it distributed the newsletter generously via AUGE channels. In the newsletter readers could register an option on a Gepard for free. 30 options were registered and 3/4 of the options were resulting in purchases. AUGE was divided in regional chapters, and in many of those chapters there was one Gepard owner, so there was always one to present a Gepard or who could be asked for opinions. As a consequence, and because of a 10% commission Gepards are mainly sold by word of mouth and by existing customers. There was also an article in the AUGE magazine (8/84) on the Gepard. Articles on the Gepard are very rare, not least because at that time, journals prefer promoting their own computer projects than reporting on a new computer with a very small customerbase. Nevertheless, Gepard also runs (small) ads in the most important computer journals. Finally, Gepard is represented with (probably very small) booths both at the Hannover Messe 1986 and at the Orgatechnik 1986.

In 1984, Apple releases the first Macintosh, also a 68000-based computer. Fortunately for Gepard, although the Mac has a mouse and a GUI, and is sold complete in a neat, compact package, it is more expensive (at DM 10,000), and it is (at 8 MHz) slower than the Gepard. It is also by and large not expandable. As also the typical customer of a Mac and a Gepard differ substantially, the Mac is no threat to the Gepard.

Until 1985 Gepard had 70% private and 30% professional customers. In the fall of 1985 Atari starts selling a new model, the Atari ST for an unrivaled low price (~DM 3,000 including floppy disk drive, monitor, mouse, and GUI) and basically ends sales of Gepards to private customers. The Gepard company does not know how to react to this competition, has not finalized all of its developments and is out of money. Eventually, 1986, the company files for bancruptcy.

In hindsight, Thomas Schumann, the former CEO of Gepard, thinks that it would probably have been possible to save the company if the management would have had more experience, and if it would have moved its focus to professional customers, offering a Unix-like operating system. After having found that the later 68020 version of the Gepard was quite unique at least on the German market for its price, I agree.

After Gepard went bust, one of the original founders, Hermann Spille founds his own company, HS Computer, to continue the Gepard business. He continues selling hard- and software from the Gepard catalogue, but also develops and sells new hardware. The most important development activity is the finalisation of the 68020 card and the development of the second version of this card. Other hardware includes:

  • a Z80 card
  • an EPROM burner

Apart from HS Computer, there are a whole number of small projects starting in the aftermath of Gepard:

  • ports of OS-9, PC DOS 2.1/GemDos, Eumel/Elan are started or at least proposed
  • version 1.4 of GDOS is finalized by Thomas Tempelmann
  • version 2.0 of GDOS is written by Harald Hellmann
  • an “Atari ST” graphics card is developed that can be connected to an Atari monitor

But eventually, over time, the Gepard business trickles off and HS Computer is liquidated in 2009.

Ok, so, here you have it. My collected findings about the German Gepard computer. I hope you liked it. It took me a long time to collect, analyse, and write, but it was fun, it was new, and it was basically never documented before (especially in English).